Post-embryonic function of GLOBULAR EMBRYO 4 (GLE4)/OsMPK6 in rice development.

In plants, mitogen activated protein kinases (MPKs) are involved in various signaling pathways that lead to biotic and abiotic responses as well as that regulate developmental processes. Among them, MPK6 and its closely related homologue, MPK3, act redundantly and are known to be involved in asymmetric cell divisions of meristemoid mother cells in stomata development and of zygotes in Arabidopsis. Loss-of-function mutants of GLE4/OsMPK6, which is an orthologue of MPK6 in rice, showed a defect in polarity establishment in early stage of embryogenesis. However, because of the embryo lethality of the mutations, the function of GLE4/OsMPK6 in post-embryonic development is not clarified. Here, we report the analysis of post embryonic function of GLE4/OsMPK6 in vegetative stage of rice using regenerated gle4/osmpk6 homozygous plants from tissue culture. The regenerated plants are dwarf and produce multiple shoots with small leaves. These shoots never develop into reproductive stage, instead, proliferate vegetative shoots repeatedly. Leaves of gle4/osmpk6 have small leaf blade at the tip and blade-sheath boundary become obscure. Stomata arrangement is also disturbed in gle4/osmpk6 leaf blade. The shape of shoot apical meristem of gle4/osmpk6 become disorganized. Thus, GLE4/OsMPK6 functions in shoot organization and stomata patterning in the post embryonic development in rice.

Specification of basal region identity after asymmetric zygotic division requires mitogen-activated protein kinase 6 in rice.

Asymmetric cell division is a key step in cellular differentiation in multicellular organisms. In plants, asymmetric zygotic division produces the apical and basal cells. The mitogen-activated protein kinase (MPK) cascade in Arabidopsis acts in asymmetric divisions such as zygotic division and stomatal development, but whether the effect on cellular differentiation of this cascade is direct or indirect following asymmetric division is not clear. Here, we report the analysis of a rice mutant, globular embryo 4 (gle4). In two- and four-cell-stage embryos, asymmetric zygotic division and subsequent cell division patterns were indistinguishable between the wild type and gle4 mutants. However, marker gene expression and transcriptome analyses showed that specification of the basal region was compromised in gle4 We found that GLE4 encodes MPK6 and that GLE4/MPK6 is essential in cellular differentiation rather than in asymmetric zygotic division. Our findings provide a new insight into the role of MPK in plant development. We propose that the regulation of asymmetric zygotic division is separate from the regulation of cellular differentiation that leads to apical-basal polarity.

Measurement accuracy of alveolar soft tissue contour using a laboratory laser scanner.

Steric analysis of morphological changes is important for evaluation of surgical techniques. This study was performed to assess the measurement accuracy of alveolar soft tissue contour with a laboratory laser scanner. The width of the maxillary alveolar soft tissue contour was evaluated in 20 volunteers. Measurement sites were established in the alveolar soft tissue contour of the maxillary incisor and canine areas. Each site was evaluated by direct measurement with a microcaliper for each subject (DMM) and image measurement using a laboratory laser scanner (IMS). The accuracy of measurement methods was evaluated. Additionally, two plaster models obtained from the same subjects were scanned and superimposed, and the nonoverlapping areas were measured. Each measurement method exhibited a strong correlation (r = 0.89). The interclass correlation coefficient (single measure) between examiners was also high for each measurement method (PMM 0.978; IMS 0.997). In the superimposed images of the two plaster models, the distance of the nonoverlapping region was only 0.06 ± 0.08 mm in the labial aspect and 0.07 ± 0.09 mm in the palatal aspect. The image measurement of the scanning data shows high accuracy in evaluation of the alveolar soft tissue contour. This technique is useful for evaluation of chronological changes in the alveolar contour after soft and hard tissue augmentation.

Effect of the Keratinized Mucosa Width on the Health Status of Periimplant and Contralateral Periodontal Tissues: A Cross-sectional Study.

INTRODUCTION: The purpose of this study was to examine whether the width of keratinized mucosa (WKM) is associated with the health status of tissue surrounding dental implants and the contralateral teeth. MATERIALS AND METHODS: Sixty patients who received implant-fixed unilateral prostheses in the premolar or molar region were recruited for the study. The following parameters were measured for each implant and contralateral tooth: WKM, gingival index (GI), probing pocket depth (PPD), bleeding on probing (BOP), pus discharge, plaque accumulation (PA), gingival recession (GR), and difficulty of brushing. The effect of the WKM on the health status of the surrounding tissue was evaluated by comparing the different WKM groups (WKM < 2 mm vs WKM ≥ 2 mm). RESULTS: Implants with a WKM <2 mm demonstrated significantly greater PPD, PA, and a higher rate of BOP compared with implants with a WKM ≥2 mm. There was significantly greater GR in contralateral teeth with a WKM <2 mm compared with a WKM ≥2 mm. In addition, implant sites had a higher rate of BOP compared with the contralateral teeth. CONCLUSIONS: Inadequate keratinized mucosa decreased cleansibility of implant sites and increased mucosal inflammation. There is a possibility that PA in implant sites caused more pronounced inflammatory response compared to contralateral tooth.

Palatal window osteotomy technique improves maxillary sinus augmentation in previously insufficient augmentation case.

INTRODUCTION: Perforation of the Schneiderian membrane is the most common complication in sinus floor augmentation (SFA). When volume of grafting is qualified to prevent enlargement of the membrane perforation, lack of bone volume may occur in optimal site. CASE PRESENTATION: SFA was performed in sites #24 to 26 in a 63-year-old male. However, a 10-mm size perforation of the Schneiderian membrane occurred in site #26. Although the sinus cavity was grafted with deproteinized bovine bone mineral (DBBM) after repair of membrane perforation, insufficient bone formation was observed on palatal and distal aspects of site #26 at 5 months after SFA. Although additional SFA was required for implant placement, it seemed to be difficult to elevate the membrane by a conventional lateral approach in the palatal aspect of the sinus floor (site #26). Considering the configuration of new bone formation, it was decided to perform the palatal antrostomy approach. The Schneiderian membrane was elevated without perforation, and the sinus cavity was grafted with DBBM mixed with venous blood. Two 12-mm long, 4.1-mm diameter implants were placed in sites #14 and 16. Four months after implant placement, abutment-connection surgery was successfully performed. The radiographic image indicated improved radiopacity, without obvious bone resorption in site #26. CONCLUSION: The palatal window osteotomy technique could be considered as an alternative method for augmentation of maxillary sinus in cases where difficulty is encountered to elevate a membrane by a conventional approach (e.g., in cases in which buccal bone height is long).